1. Field of the Invention
The present invention relates to a system and method for detecting particles produced in a semiconductor process chamber by scattering light.
2. Description of the Related Art
Some of the most common defects of semiconductor wafers are created by particles. The particle may remain on the wafer and be visible as a short circuit between lines or a boulder that the upper layers cannot cover. A particle detection system is described in Journal of Vacuum Science and Technology, B9(6), November/December 1991, pages 3487-3492 and A 14(2), March/April 1996, pages 649-654 (Gay. S. Selwyn). According to this particle detection system a rastered laser beam is injected into a process chamber and light scattered by particles is detected by a CCD camera and displayed on a monitor screen. Because the displayed particles are inspected by human eyes, it takes a long time to determine whether particles are present or not. Another disadvantage of the prior art system is that it lacks precision.